1. Field of the invention
The present invention relates to a medical examination bed notably for a nuclear magnetic resonance (RMN) apparatus or a tomodensitometry apparatus. It is mainly used in the medical field where it is known that patients are made to lie down for non-invasive examinations with such machines.
2. Discussion of the Background
This type of examination is particular in that, in general, it takes a long time to perform. To improve the comfort of the patient, it may then be necessary to ventilate the machine examination tunnel and to illuminate and conduct dialogue with the patient. In all cases, it is also necessary to provide constant supervision of the latter. Indeed, patients going through such examinations are generally not in good health and because of this, may be upset by the examination resulting in them not feeling well. Under these conditions, they must be removed from the machine as quickly as possible. Under normal use, the insertion of the patient in the machine, on a plateau or a patient-support panel, is initiated by the starting of motors. These motors may be electrical. In the case of RMN, it is desirable to have them installed as far as possible from the examination tunnel so as not to interfere with the consistency of the magnetic field, through metallic mass. But the indisposition of the patient may be caused by a cut-off of power. The patient will be aware of the cut-off of lighting, ventilation and of supervision means and will feel some anguish. Intervention or extract of the patient from the machine is then rendered difficult because the plateau manipulation motors will have falled because of the lack of current. But because of the mechanical ratios and the demultiplication of these motors, it is unthinkable to attempt to turn the transmission chain backward by hand.
In addition, examination beds may be used for entering patients into the machine and in some cases bringing them into their bedrooms when examination is over. Therefore, the beds can be disconnected from the machines. This requirement of bed mobility is incompatible with the nature of the examination being undertaken. Indeed, for such examinations, images, sectional views of parts of the patient's body are taken. These images and sectional views correspond to particular parts of the patient's body. Therefore, it is necessary to identify and move precisely the part of the body to be imaged level with the imagery means. Consequently, when the bed is plugged into the machine, it is essential to bring the means for movement of the patient support panel on the bed to correspond exactly with the means for movement of the panel in the machine. To avoid this difficulty, long panels have been imagined, i.e. 3,50 meters long, still having one end engaged in the bed while the other is entered freely into the apparatus. It can be demonstrated that although already long, this panel may be insufficiently long to permit examination of the whole body. In this case the direction of patient presentation has to be inverted when the need arises. In addition, a long bed is difficult to manipulate through hospital corridors.